A refreshable Braille display is an electromechanical device including multiple tactile cells. The Braille display can be connected to a computer by way of a wired or wireless connection. Typical Braille displays include 20, 40, or even 80 cells. Each cell, in turn, contains six or eight tactile pins that move up and down in response to electrical voltage. The tactile pins can be driven by mechanical, electromechanical, piezoelectric, pneumatic, or magnetic effects. When in the raised position, the pins extend above a tactile surface and can be felt by a user. By raising certain pins and keeping others below the tactile surface, individual Braille characters can be represented. The series of cells together represent a line of text. After a line has been read, the user can refresh the display to allow for additional lines to be presented and read. Braille displays are often combined with other hardware and software to make up an integrated unit. For instance, Braille displays can be connected in place of video monitors to serve as the display unit, and many units incorporate speech output of the screen prompts. In this regard, computer software can be employed to convert a visual image in a screen buffer of the computer into text to be displayed on the Braille display.
Electromechanical tactile cells for use in refreshable Braille displays and graphical tactile displays have been developed. One example of a tactile cell includes eight piezoelectric reed elements corresponding to eight tactile pins. The necessary electrical connections and driving forces are provided to actuate the reeds, thereby causing the tactile pins to protrude above a tactile surface to allow the Braille character or graphic element to be displayed. However, such electromechanical tactile cell structures require significant tolerances and power requirements. Additionally, alternative electromechanical tactile cell structures may experience longevity issues due to the use of fluid displacement amplifiers and rubber seals. Braille-pin and -cell lateral spacing is sufficiently small, and vertical displacement, speed, and blocking force sufficiently large, that implementing refreshable Braille under NLS-specified tolerances has been a difficult fit for many technologies.
In view of the foregoing, there is a need for improved Braille displays.